Cops have ruled out a person of interest in one of the murders committed by the Brooklyn serial killer, saying that the subject of a police sketch released in August has no connection to the slayings.

NYPD Commissioner Ray Kelly said the man in the sketch circulated after the Aug. 2 Bensonhurst murder of Isaac Kadare, 59, was in the area at the time.

“That was a sketch that surfaced with one of the previous murders, it is no longer relevant,” said Kelly. “That individual washed out again. That individual was somebody we wanted to talk to, who may have been in the area. He’s not a subject, he’s a person we simply wanted to speak to.”

“It was someone that we wanted to speak to in the area. I believe that individual was interviewed.”

Cops are still hunting for a mysterious man toting a duffel bag identified as a key “person of interest” after surveillance video showed him at one — and possibly two — of the three slay scenes, law-enforcement sources told The Post yesterday.

“We would obviously like that individual to come forward and contact us,” Kelly said today.

The unidentified man — dubbed “John Doe Duffel Bag” — who is middle-aged, white and balding, was most recently caught on surveillance video, duffel bag in hand, at around 6 p.m. Friday near the Flatbush store where owner Rahmatollah Vahidipour, 78, was found dead at 7:11 p.m., cops said.

Another video appears to show the same man near a Bensonhurst shop around the time its owner Kadare was killed, several sources said yesterday.

Kelly today disputed the claim that he was spotted at older murders.

“That’s not the case,” he said.

The duffel man has no known connection to the first murder of shopkeeper Mohammed Gebeli, 65, in his Bay Ridge clothing store on July 6.

All three murders were committed with the same .22-caliber handgun, and all three occurred while the lone business owner was closing up shop.

All three bodies were also covered when they were discovered, cops said.

“It may be significant, it may not, but in all three cases, the victim’s head was covered either by cardboard or clothing of some sort,” said Kelly.